Specifications

To work out current/battery capacity requirement (for 12V system):
Power (Watts) / 12V = Current hour (Ah)
This is the rough calculation for the size of a vehicle alternator you would need to keep up with a
specific load, as an inverters efficiency is only rated around 90%, the current requirement will need
to be 10% higher; for example, to keep up with a continuous draw of 1000W, you would need:
(1000 ÷ 12) × 1.1 = 91.67Ah
Therefore an alternator with minimum output current of 91.67A at 12V is required to run
continuously. Alternatively a fully charged 12V battery with capacity of 91.67Ah can run continuously
for around an hour.
How do I connect the Inverter? What size cable should I use, and is it included?
Many small inverters (300W and under) come with crocodile clips which are attached to the positive
and negative terminals of the battery.
Larger inverters (500W and over) must be hard-wired directly to a battery. The cable size depends
on the distance between battery and inverter, and will be specified in the instruction manual for the
inverter.
When connecting the inverter to the battery use the thickest wire available, in the shortest length
practical.
General recommendations: (cable sizes are expressed as AWG)
Inverter Power Output
< 1m
1m – 2m
2m – 3m
600W
6
4
2
1000W
4
2
1/0
1500W
2
1
3/0
2500W
1/0
3/0
350
NOTE: These are general recommendations for inverters that utilise a single cable set (one positive
and one negative cable) only and may not be correct for all inverters or applications. Additionally,
some inverters require two or more cable sets and therefore may require a different cable size than
listed.
Cable size recommendations may vary among inverter brands and models; please check the
Instruction manual for the model you have purchased before you buy the wire for it.
The maximum length generally recommended is 3m, and shorter runs are recommended to reduce
resistance and heating effect of the cable and improve the efficiency. If longer distance is required
from battery to the device, it is recommended to extend from the AC output rather than on the DC
input side.